Three of the most controversial figures of Sudan's ruling Transitional Military Council have offered their resignations - one of the key demands of the protest movement.
The three were seen as staunch Islamists and allies of the deposed President, Omar al-Bashir.
It follows talks between the military council and protest leaders.
A "million-strong march for civilian rule" has been called later to maintain the pressure for democratic reform.
Thousands of protesters have arrived in the capital, Khartoum, by train from various cities to take part in the event.
Protest leaders have been calling on the Transitional Military Council to hand over to a civilian administration.
At a press conference on Wednesday, military spokesman Lt-Gen Shamseddine Kabbashi said the two sides had reached agreement on most of the demands, and that they decided to set up a joint committee to bridge their differences.
The three generals stepping down are Omar Zain al-Abideen, Jalal al-Deen al-Sheikh and Al-Tayeb Babakr Ali Fadeel.